GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Analog Playback
In the Thread: The last phonocorrector: “End of Life" Phonostage

Post Subject: GND planePosted by N-set on: 11/22/2011

Paul S wrote:
Is the "ground plane" in this case literally a sheet of copper that you run all the grounds to? If so, this may be overkill on the one hand and an antenna/noise magnet/generator on the other hand, and/or it may well make for ground loops.

Oh, this is a very controversial statement Paul! The 2D sheet of thick copper (or in my case actually semi-3D as the Cu is 1.5mm thick)
has vanishing inductance and resistence. Thus it's antena action is zero so is it's resistance in any "ground loop". Thus no loop.
Think that various induced currents have a much more space to distrubute themselves properly. I have zero experience with RF,
but, the common knowledge there says a 2D sheet provides an ultimate ground.

Paul S wrote:
It is usually sufficient to have a ground "bus" that is not connected to the chassis, and this goes out on the neutral wire. Parts should not directly touch the copper sheet or the chassis; stand them off mechanically and electrically. The chassis and your IC shields can use the "dedicated" ground. The "house" ground is lifted at the chassis/not used for the phono stage.

Again, bus is semi 1D, it has higher self inductance than a plane and so it's antena action is stronger. Yes, all the parts are lifted from the GND plane/chassis. I use house earth for the safety of experimentation-I don't want to electrocute myself before I finish the phono.

Cheers,

Nset

Rerurn to Romy the Cat's Site